Evaluation of type B Clostridium perfringens growing conditions and the production of toxins for veterinary vaccines production

Clostridium perfringens tipo B, bactéria anaeróbia, heterofermentativa, gram-positiva e produtora de toxina, é importante agente causador de doenças entéricas em animais. As toxinas inativadas α, β e ε produzidas por esse microrganismo estão presentes na composição das vacinas veterinárias contra clostridioses. Neste trabalho, estudou-se o efeito da composição do meio de cultura e do pH sobre o crescimento e produção de toxinas por Clostridium perfringens Tipo B para produção de vacinas veterinárias. Foram estudadas as concentrações iniciais da glicose e a presença de diferentes hidrolisados protéicos no meio – peptona de carne e peptona de caseína – e suas combinações. Os experimentos foram realizados em culturas conduzidas sob regime de batelada, com o uso de meio basal recomendado na literatura, observando-se a produção máxima de toxinas. Amostras foram coletadas a cada hora para determinação da concentração de células, ácido lático, ácido acético, ácido propiônico, ácido fórmico, etanol e glicose. Os melhores resultados foram obtidos quando o pH foi mantido em 6,5, utilizando-se 10,0 g.L-1 de glicose e 10,0 g.L-1 de hidrolisado protéico. A origem da proteína não teve influência significativa sobre o cultivo e a produção de toxinas. Pela análise da cinética de crescimento e produção, evidenciou-se que a formação de toxinas está associada ao crescimento. O presente estudo permitiu encontrar parâmetros satisfatórios de cultivo, que foram utilizados na ampliação de escala para produção industrial de vacinas contra clostridioses causadas por C. perfringens tipo B.Type B Clostridium perfringens, anaerobic, hetero-fermentative, gram- positive and toxin producer bacteria is an important agent of enteric diseases in animals. The α, β and ε inactivated toxins produced by this microorganism are present in the composition of veterinary vaccines against diseases. In this work, the effects of culture medium composition and pH on growth and toxin production by the bacteria were studied. The initial glucose concentrations and the presence of different hydrolytic proteins in the medium – meat peptone and casein peptone – and their combination, were studied. The experiments were conducted in the batch system, using basal medium as recommended by literature. The best results were obtained when pH was kept at 6.5, using 10.0 gL-1 glucose and 10.0 gL-1 hydrolytic protein. The variation of the protein origin had no significant effect on the growth and toxin production. The analysis of the growth kinetics and production indicated that toxin formation is associated with growth. The present study permitted the finding of optimum growth parameters which were used in the amplification of scale for industrial production of vaccines against clostridial diseases caused by type B Clostridium perfringens.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Efeito in-vitro de nisina sobre pool de Staphylococcus aureus isolados de queijos minas artesanal da região do Campo das Vertentes-MG

Minas traditional cheeses currently have a prominent role in the scientific depending on their social and economic importance to the country legally. Although the cheese can be marketed within the state, is notorious its presence outside of Minas Gerais. Because it is made with raw milk, the cheese has a risk for consumers to be potential carrier of pathogens such as Listeria, Salmonella and Staphylococcus aureus. The use of raw milk implies the need for studies to significantly decrease their contamination by S. aureus. Studies have shown that the addition of nisin to cheese manufacturing process can significantly reduce the contamination. The aim of this study was to evaluate the effect of Nisin on pool S. aureus isolates from traditional cheeses of Campo das Vertentes. Four levels (100, 200, 400 and 500 IU. mL-1) of the commercial preparation Nisaplin ® in autoclaved reconstituted skim milk at 10%. The analysis of S. aureus were made using 3M Petrifilm at zero; 3, 5, 8, 10, 12, 16, 24, 36, 48, 72, and 96 of incubation. There was no significant difference (p > 0.05) between control and doses of 200 IU mL-1. However differences were observed between the other doses (p <0.05) in the two mentioned and also among themselves. The results of this study confirm those already made elsewhere showing that nisin can be effective in reducing counts of S. aureus in cheeses made with raw milk.Queijos artesanais têm atualmente papel de destaque no cenário científico em função da sua importância social e econômica para o País. Embora legalmente o queijo só possa ser comercializado dentro do Estado, é notória a sua presença fora de Minas Gerais. Pelo fato de ser elaborado com leite cru, o queijo apresenta risco para os consumidores por ser potencial carreador de micro-organismos patogênicos como Staphylococcus aureus. A obrigatoriedade da utilização de leite cru implica a necessidade de estudos para diminuir consideravelmente a contaminação dos mesmos por S. aureus. Estudos mostraram que a adição de nisina ao processo de fabricação dos queijos podem diminuir a contaminação consideravelmente. O objetivo desse estudo foi avaliar o efeito da adição de nisina sobre pool de S. aureus isolados de queijos Minas artesanais do Campo das Vertentes. Foram testadas quatro doses (100; 200; 400 e 500 UI. mL-1) do preparado comercial Nisaplin® em leite autoclavado desnatado reconstituído a 10%. As análises de S. aureus foram feitas utilizando-se Petrifilm nos tempos zero; 3, 5, 8, 10, 12, 16, 24, 36, 48, 72 e 96 de incubação. Não houve diferença significativa (p > 0,05) entres o controle e a doses de 200 UI mL-1. No entanto foi observada diferença entre as demais doses (p<0,05) em relação as duas mencionadas e também entre elas próprias. Os resultados obtidos neste trabalho corroboram os já realizados em outras regiões mostrando que a nisina pode ser efetiva para redução das contagens de S. aureus em queijos elaborados com leite cru

Antioxidant activity of essential oils from condiment plants and their effect on lactic cultures and pathogenic bacteria

ABSTRACT: Studies about preservative and antioxidant activity of essential oils have been encouraged in recent years, given their importance to food industry. The aim of the current study was to evaluate the antioxidant properties and antimicrobial activity of essential oils deriving from Syzygium aromaticum, Cymbopogon citratus and Lippia alba against lactic and pathogenic bacteria responsible for food-borne diseases. Essential oil antibacterial activity was assessed through disc diffusion and macrodilution tests conducted in a mixed lactic culture of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus (YF-L903) and of Escherichia coli (ATCC 8739), Staphylococcus aureus (ATCC 6538), Salmonella enterica (ATCC 6017) strains. Based on the chromatographic analysis results, the essential oils shown to be composed of eugenol (79.41%) which was the prevalent compound in S. aromaticum, geranial (31.89%), neral (24.52%) and β-myrcene (25.37%) in C. citratus, as well as of geranial (33.80%) and neral (25.63%) in L. alba. The observed antibacterial activity confirmed the dose-dependent effect of these three oils on all the assessed bacteria; there was halo inhibition at concentration 20μL mL-1. The essential oil of S. aromaticum presented better antioxidant activity, with IC50 equal to 5.76μg mL-1 and antioxidant activity index of 6.94, and it was considered strong (AAI>2.0) in comparison to the other evaluated oils. This essential oil also presented excellent antioxidant activity at concentrations lower than the one required to inhibit lactic cultures. Based in this outcome, the essential oil from S. aromaticum can be used as preservative agent in processed food whose formulation presents lactic cultures

Toxicidade aguda dos extratos hidroalcoólicos das folhas de alecrim-pimenta, aroeira e barbatimão e do farelo da casca de pequi administrados por via intraperitoneal Acute toxicity of leaf hydroalcoholic extracts of Lippia sidoides, Myracroduon urundeuva, Stryphnodendron adstringens and of Caryocar brasilliense administered by intraperitoneal route

O estudo objetivou realizar ensaio toxicológico pré-clínico inicial para investigar a toxicidade das folhas de alecrim-pimenta (Lippia sidoides Cham.), aroeira (Myracrodruon urundeuva Fr. All.) e barbatimão [Stryphnodendron adstringens (Mart.) Coville] e do farelo da casca de pequi (Caryocar brasiliense Camb.), por meio da determinação da dose letal 50% (DL50). Na investigação da DL50, foram utilizados grupos de camundongos Swiss de mesmo sexo (n=150, sendo 30 animais por tratamento) inoculados, por via intraperitoneal, com diluições seriadas do extrato hidroalcoólico das folhas de alecrim, aroeira e barbatimão e do farelo da casca de pequi. Após a inoculação, os animais foram observados por um período de 14 dias, para determinar a quantidade de mortos, doentes e sobreviventes. O estudo toxicológico pré-clínico agudo demonstrou, em camundongos por via intraperitoneal, toxicidade igual a 0,31mg mL-1 DL50 mL-1 para todas as plantas, exceto para o barbatimão, que apresentou toxicidade igual a 0,25mg mL-1. Pesquisas devem ser realizadas visando a obter dados de toxicidade das plantas em outras vias para assegurar o uso em saúde humana e animal.This study aimed to conductpre-clinical toxicology testing to investigate the toxicity of Lippia sidoides Cham., Myracrodruon urundeuva Fr. All., Stryphnodendron adstringens (Mart.) Coville and Caryocar brasiliense Camb., by determining the 50% (LDL50) lethal dose. In the investigation of the LD50, groups of Swiss mice of the same sex were used (n=150; 30 animals per plant and all inoculated intraperitoneally with serial dilutions of the aqueous fraction obtained from the leaves of plants. After inoculation, the animals were observed along a period of 14 days in order to observe the dead, sick and survivors rate. In mice inoculated intraperitoneally, the acute pre-clinical toxicology testing demonstrated toxicity equal to 0,31mg mL-1 LD50 mL-1 for all plants. The exception was for Stryphnodendron adstringens, which presented toxicity equal to a 0,25mg mL-1DL50 mL-1 and values expressed in terms of dilution. Research should be conducted to obtain data on toxicity of the plants in other ways to ensure the use in human and animal health. Therefore, the studied plants should be used with caution. They present a relatively mild toxic potential, but it may be harmful to users if they are not properly utilized

Characterization of the Primary Sludge from Pharmaceutical Industry Effluents and Final Disposition

The generation of large volumes of waste by industrial processes has become an object of study because of the necessity to characterize the composition of residues in order to suggest appropriate treatments and to minimize adverse environmental impacts. We performed analyses of total fixed and volatile solids, moisture, and chemical oxygen demand (COD). We found high organic matter content. We also measured physicochemical characteristics, including corrosivity, reactivity, and toxicity. Sewage sludge showed levels of chloride and sodium above the maximum allowed limits. These data suggest the potential for anaerobic digestion as a treatment option for sewage sludge and for its use as a biofertilizer